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There is currently no evidence that the intervertebral discs (IVDs) can respond positively to exercise in humans. Some authors have argued that IVD metabolism in humans is too slow to respond anabolically to exercise within the human lifespan. Here we show that chronic running exercise in men and women is associated with better IVD composition (hydration and proteoglycan content) and with IVD hypertrophy. Via quantitative assessment of physical activity we further find that accelerations at fast walking and slow running (2 m/s), but not high-impact tasks, lower intensity walking or static positions, correlated to positive IVD characteristics. These findings represent the first evidence in humans that exercise can be beneficial for the IVD and provide support for the notion that specific exercise protocols may improve IVD material properties in the spine. We anticipate that our findings will be a starting point to better define exercise protocols and physical activity profiles for IVD anabolism in humans.
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Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
Running exercise strengthens the
intervertebral disc
Daniel L. Belavý1, Matthew J. Quittner1, Nicola Ridgers1, Yuan Ling2, David Connell2,3 &
Timo Rantalainen1
There is currently no evidence that the intervertebral discs (IVDs) can respond positively to exercise in
humans. Some authors have argued that IVD metabolism in humans is too slow to respond anabolically
to exercise within the human lifespan. Here we show that chronic running exercise in men and
women is associated with better IVD composition (hydration and proteoglycan content) and with IVD
hypertrophy. Via quantitative assessment of physical activity we further nd that accelerations at fast
walking and slow running (2 m/s), but not high-impact tasks, lower intensity walking or static positions,
correlated to positive IVD characteristics. These ndings represent the rst evidence in humans that
exercise can be benecial for the IVD and provide support for the notion that specic exercise protocols
may improve IVD material properties in the spine. We anticipate that our ndings will be a starting point
to better dene exercise protocols and physical activity proles for IVD anabolism in humans.
We expect that tissues will adapt to loads placed upon them. Wol1 described the theory of bone adaptation to
loading. In the intervening years, evidence2 has been obtained as to which loading protocols are benecial (oste-
ogenic) for bone. For the intervertebral disc (IVD), little is known about what loading protocols are benecial
for IVD tissue and cause anabolism in humans. We have good knowledge of loading types that are more likely to
damage lumbar IVD tissue in humans, such as exion of the spine with compression3, torsion4 or to damage to
the vertebral end-plate via axial compression3 with subsequent IVD degeneration5. Whilst this information can
inform what activities people should avoid to preserve IVD integrity, it does not inform us on exercise or habitual
physical activity to “strengthen” the IVD. Furthermore, data6 on turnover rates in the IVD, lead to the assumption
that positive adaptation in the mature IVD is unlikely to occur during the normal human lifespan.
Currently we rely on data from animal, IVD cell and IVD tissue models to suggest what kind of loading might
be benecial for the human lumbar IVD. ese models suggest7 that a “likely anabolic loading window” for the
IVD exists: dynamic loading of 0.2–0.8 MPa, generating intra-discal pressures of approximately 0.3–1.2 MPa, at
0.1 to 1 Hz for approximately eight hours a day. Given human data on intra-discal pressures in dierent activities8,
this could9 be extrapolated to suggest that walking or running exercise is likely anabolic for the IVD. Quadrupedal
treadmill running exercise in rodents10,11 can have a positive impact on the rodent IVD. However, directly apply-
ing loading thresholds and protocols from animal models to humans is problematic12 and there is no evidence
yet9 of a benecial eect of exercise on the IVD in humans. We aimed to determine whether benecial eects on
the IVD of exercise can be seen in humans and what loading patterns this might entail.
Our hypothesis was that people who perform regular upright running activity will show better IVD tissue
quality, as shown by higher T2-times13 in their lumbar IVDs, than people who are healthy with no history of spi-
nal disease, but otherwise not physically active. We also hypothesised that there would be a dose-response eect
of dierent volumes of running. Furthermore, to better understand what types of physical activity are likely ben-
ecial for IVD, we explored the relationship between habitual physical activity, as measured by objective accel-
erometry, and IVD characteristics. To reduce the confounding inuence of normal aging on our ndings, and
given evidence9 that IVD maturation is still in process in the third decade of life, we included women and men
aged 25–35 years. It is also not clear how long is required before the IVD might show a measurable adaptation
to exercise, and we therefore recruited only people with a minimum of 5 years history at their current physical
activity level: either no sport (referents), 20–40 km per week running (joggers), or 50 + km per week running
(long-distance runners).
1Deakin University, School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, 221
Burwood Highway, Burwood, Victoria, 3125, Australia. 2Imaging at Olympic Park, 60 Olympic Boulevard, Melbourne,
Victoria, 3004, Australia. 3Monash University, Wellington Road, Clayton, Victoria, 3168, Australia. Correspondence
and requests for materials should be addressed to D.L.B. (email:
Received: 24 November 2016
accepted: 07 March 2017
Published: 19 April 2017
Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
Long-distance runners (Table1) and joggers showed signicantly higher (+ 11.4% and + 9.2% respectively) lum-
bar IVD T2-times than the non-athletic individuals (Fig.1). is eect was also present at all individual vertebral
levels T11/T12 to L5/S1 (Fig.2; upper panel). e eect of running on T2-time was strongest in the IVD nucleus
(Fig.3; + 11% in joggers and + 15% in long-distance runners in the central nuclear region versus + 5% to + 6%
respectively in the anterior annulus and + 5% and + 9% respectively in the posterior annulus). e height of the
IVD relative to that of the vertebral body, an indicator of IVD hypertrophy, was greater in the long-distance run-
ners (Fig.1). When examining individual vertebral levels (Fig.2; lower panel), this eect was present at the lower
No spor t
(20–40 km)
(50 k + )
Number of males (of
total N) 11 of 24 13 of 30 11 of 25
Body mass (kg) 73.9(17.8) 68.2(11.1) 63.5(10.2)*
Age (yrs) 29.3(3.7) 30.2(3.2) 30.1(3.9)
Height (cm) 173.2(8.7) 173.6(9.7) 170.3(9.2)
Weekday sitting time
(hrs) 9.7(2.1) 6.3(2.8)‡ 6.4(2.8)‡
participation (yrs) - 8.8(4.2) 7.6(3.9)
participation (hrs/
- 4.9(2.2) 8.6(4.3)
Exercise distance
(km/wk) - 28.0(6.7) 66.6(19.5)
IVD volume (cm3) 9.5(2.3) 10.1(3.4) 10.1(3.3)
IVD average area
(mm2)250.2(41.2) 263.6(60.8) 263.0(58.9)
IVD height (mm) 7.1(0.7) 7.3(1.1) 7.5(1.0)
IVD anteroposterior
width (mm) 25.6(2.4) 26.4(3.5) 25.9(3.4)
distance (mm) 34.2(2.0) 34.1(2.9) 34.0(2.8)
Prrmann grade 2.3(0.39) 2.2(0.39) 2.1(0.39)
Erector spinae size
(cm2)14.3(3.3) 14.4(5.0) 14.1(4.8)
Lumbar multidus
size (cm2)4.7(1.1) 4.4(1.6) 4.1(1.6)
Psoas size (cm2) 9.1(2.8) 10.1(4.2) 9.6(4.0)
lumborum size
3.5(1.1) 3.4(1.7) 3.1(1.6)
Table 1. Participant characteristics, intervertebral disc characteristics and lumbar muscle morphology.
Values of continuous variables are mean(SD). *p < 0.05; p < 0.01; p < 0.001 and indicate signicance of
dierence to the non-sporting group. e proportion of females:males did not dier across groups (χ
2 = 0.01,
p = 0.99). ree participants were of Asian descent (one female 20–40 km runner, one male 20–40 km runner,
one male 50 + km runner) and the remaining participants were Caucasian. Prrmann grade was averaged from
all lumbar discs. Areas of erector spinae, multidus, psoas and quadratus lumborum muscles were averaged
from le and right sides of the body and all lumbar levels.
Figure 1. Runners have more hydrated (le) and hypertrophied (right) lumbar IVDs. Values are
mean(SD) averaged across all lumbar discs. Le panel: Higher T2-times indicate13 better IVD hydration and
glycosaminoglycan content. Right panel: IVD height relative to vertebral body height. *p < 0.05; p < 0.01 and
indicate signicance of dierence to the non-sporting group.
Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
lumbar vertebral levels L3/L4 to L5/S1. Lumbar muscle size did not dier between groups (Table1). e eect of
running exercise was consistent for both genders, with the gender × group interaction not reaching signicance
(p > 0.18). e long-distance group typically showed greater dierences in IVD parameters to the non-sporting
group than the jogging group. However, there were no statistically signicant dierences between the two run-
ning groups.
Total physical activity levels, as measured by objective accelerometry, were not related to IVD characteristics
(Fig.4). Rather, IVD nucleus T2-time was most strongly associated with accelerations in the range 0.44 and 0.59 g
mean amplitude deviation (MAD; Fig.5). Additional accelerometry data collected under dierent exercise con-
ditions in ten individuals (SupplementaryTable1) showed that ambulation at 2 m/s fell inside this 0.44 and 0.59 g
MAD range. Walking at 1.5 m/s or slower fell below this range and running at 2.5 m/s or faster and jumping were
above this range.
Before the rst interventional studies to dene exercise regimes for improving bone characteristics were per-
formed in the 1990s, an important step was the nding of dierences in bone density between dierent athletic
populations14. is built on prior animal studies and helped to show that exercise may well result in anabolic
adaptation of bone. In this vein, the current study builds on prior work in animal, cell and tissue explant models7
and provides the rst ever cross-sectional evidence in humans that exercise may well favourably impact the IVD.
Our main nding was that long-distance runners and joggers showed better hydration and glycosaminogly-
can levels (higher lumbar IVD T2-times13) than the non-athletic individuals. is is consistent with ndings of
an anabolic response in the IVD in quadrupedal animals10,11 to running. e nding is also consistent with the
notion, developed on the basis of cell, tissue explant and animal models7,15, of a “likely anabolic window” for
IVD loading. e eect of running in humans on IVD composition was most obvious in the IVD nucleus where
intra-discal pressure increases with applied axial load are constrained by the ring-formed annular bres16.
Beyond the compositional dierences, there was evidence of IVD hypertrophy in the long-distance runners.
e height of the IVD relative to that of the vertebral body, which serves as an internal control for body size, was
greater in the long-distance runners. is extends on ndings17 from monozygotic twins that IVDs were margin-
ally, but not signicantly, larger in those twins that were at least 8 kg heavier than their twin pair and presumably
experienced greater habitual spinal loading. Hypertrophy of the IVD may well be an adaptation to habitual load-
ing in runners. Similar to hypertrophic responses seen in muscle due to resistance training18, this suggests that
tissue adaptation will occur in the IVD with exercise. Overall our ndings provide support for the hypothesis that
an adaptive, anabolic and hypertrophic response is possible in the human IVD with exercise.
e current study also provides some guidance on what kinds of loading protocols may be better for the IVD.
To understand what kinds of physical activity in humans might be the drivers of an anabolic response in the IVD,
we examined the physical activity patterns of our collective via objective accelerometry. Total physical activity
levels were not related to positive adaptations in the IVD, rather accelerations in a specic range. e strongest
association to higher IVD T2-times were seen between 0.44 and 0.59 g mean amplitude deviation. is ts with
the idea from animal, tissue and cell models7 of a “likely anabolic window” for the IVD. To better understand
what kinds of activities generate these acceleration magnitudes, we collected additional accelerometry data under
dierent conditions. Walking or slow running at 2 m/s fell inside this range with slower walking falling below this
range. Fast running and high-impact jumping activities were above this range. is is in line with the notion that
high-impact loading is considered7,19 to be detrimental to the IVD and vertebral end-plate. Dynamic IVD load-
ing of 0.2–0.8 MPa, generating intra-discal pressures of approximately 0.3–1.2 MPa, is thought7 to be an optimal
loading magnitude for the IVD. Based upon data on in vivo intradiscal pressures8, activities such as walking and
running, but not liing a 20 kg load or lying down, fall into this loading magnitude window. is corresponds
well to our observations here of the impact of exercise in athletes. We also noted that sedentary activities were
unrelated to IVD characteristics. In light of prior work, the results of our study suggest that, in comparison to
other locomotor activity, fast walking or slow running may provide the strongest anabolic stimulus for adaptation
in the IVD in humans.
Whilst the long-distance running group showed consistently better IVD properties than the jogging group,
there were no statistically signicant dierences between the two. Also, there was no relationship between the
IVD characteristics and physical activity in the 0.7 to 0.9 g MAD range where the physical activity associated with
running was most evident (SupplementaryFigure1). is indicates a ceiling eect of exercise for the IVD was
approached for both volume of upright axial spine loading and intensity. A ceiling eect in relation to exercise
has been observed for muscle hypertrophy20 and bone adaptation to exercise21. It is possible that high volume or
intensity running is not required for a benecial adaptation in the IVD.
In the wider population, it is the lower lumbar IVDs that are most commonly aected by degeneration22.
Furthermore, repetitive loading of the spine is considered23 to be a contributory factor to the development of IVD
degeneration. Despite repetitive loading of the spine during running, the exercise groups of the current study
did not show any detrimental eects at these lower lumbar segments. In contrast, the long-distance runners and
joggers showed evidence of better IVD hydration and glycosaminoglycan content in the lower lumbar spine than
those that did not perform sport. Furthermore, the evidence for IVD hypertrophy subsequent to habitual run-
ning was strongest at the lower lumbar levels. Our data show that repetitive axial loading of the spine under body
weight during running in otherwise healthy people may well be benecial for the lower lumbar IVDs.
It is important to consider some of the limitations of the current study. We performed a cross-sectional study
as a rst step to examine whether certain types of exercise might be benecial for the IVD in humans. In this
design it is not possible to completely rule out other confounding factors. We showed, for example, that lumbar
muscle size was similar in all groups and this indicates that muscle adaptation per se is not the likely cause of
Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
Figure 3. e impact of running on the disc is strongest in the nucleus. Top: 3D plot of mean T2-time across
entire IVD volume. Bottom: At the mid-line (sagittal) portion of the IVD the impact of running can be seen to
be greatest in the central, nuclear, portion of the IVD. *p < 0.05; p < 0.01 versus non-sporting group. Greater
T2-times indicate13 better IVD hydration and glycosaminoglycan content.
Figure 2. Eect of running is also present at lowest lumbar vertebral levels: T2-time (top) and IVD height
relative to vertebral body height (bottom). Values are mean(SD) at each vertebral level. *p < 0.05; p < 0.01;
p < 0.001 and indicate signicance of dierence to the non-sporting group. VB: vertebral body.
Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
dierences in IVD characteristics in our populations. However, we cannot rule out other factors such as dif-
ferences in muscle function, dierences in nutrition, systemic hormonal (e.g. growth factors, cytokines, stress
hormones) dierences, or other indirect eects. To denitively determine that the mechanical loading from spe-
cic exercise forms result in positive adaptations in the IVD, to determine mechanisms of action, and delineate
exercise guidelines for strengthening the IVD, randomised controlled exercise trials are necessary.
at an optimal loading level and pattern for the IVD exists makes sense from a tissue homeostatis perspec-
tive. Given that tissues such as bone21 and muscle18 have optimal loading conditions for an anabolic response, for
the IVD we should expect it to be no dierent. Our ndings support the perspective that, when loaded appropri-
ately, anabolic IVD adaptation can occur in humans and that this can occur on time frame for it to be meaningful
within the human lifespan.
Evidence that the IVD will respond anabolically in humans to certain types of loading may have public health
implications. Spinal pain consistently presents one of the greatest costs to developed societies for disability and
lost productivity, including when increased death rates in other diseases are accounted for24. IVD degeneration
and herniation is one important contributing factor to spinal pain. Similar to understanding the impact of specic
exercise in other disease constellations, for example in type II diabetes25, knowing that the IVD can respond to
certain kinds of loading, and understanding what kinds of loading are optimal, will result in better exercise guide-
lines for the prevention and management of spinal pain.
Figure 4. Total physical activity levels were unrelated to IVD characteristics. Empty symbols = males, lled
symbols = females. Individual values for each subject shown. ere was no correlation between total physical
activity levels and T2-time in the intervertebral disc (IVD) nuclear region.
Figure 5. Specic loading levels impact the IVD nucleus T2-time. Values are mean(95% CI) correlation
between IVD nucleus T2-time and count data in each mean amplitude deviation bin. e strongest association
to higher IVD T2-times were seen between 0.44 and 0.59 g. is corresponds to fast walking and slow jogging
(see Results and SupplementaryTable1).
Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
Ethical approval and subjects. e study was approved by the Deakin University Faculty of Health,
Medicine, Nursing & Behavioural Sciences human ethics advisory group. All subjects gave their informed writ-
ten consent prior to participation in the study. All methods were performed in accordance with the relevant
guidelines and regulations. To reduce the impact of normal ageing on the ndings, only individuals aged 25 to
35 years of age were included. Exclusion criteria included current spinal pain, history of spinal surgery, history of
traumatic injury to the spine, known scoliosis for which prior medical consultation was sought, current or prior
smoker, known claustrophobia and possible pregnancy. We recruited three groups of people with distinct loading
histories: joggers (20–40 km per week), long-distance runners (50+ km per week) and non-sporting referents.
To be included in the jogging group, subjects needed to have been running 20–40 km per week for a minimum
of the last 5 years and perform no other sport or exercise type more than once per week. Long-distance runners
were required to have performed at least 50 km per week for a minimum of the last 5 years and, with the exception
of resistance exercise for muscle hypertrophy (muscle hypertrophy training is a common training component
of long-distance runners), no other sport or exercise type more than once per week. Included in the “no-sport”
group were individuals who performed no regular sport or exercise in the last ve years, currently performed
less than 150 minutes of moderate activity (dened as activity that “causes an individual to breathe harder than
normal”) per week26, and walked less than 15 min to or from their place of work. A total of 79 participants were
included in the study (Table1).
Testing and scanning protocol. Participants were instructed not to perform any exercise on the day of
their scan. Due to normal diurnal variation in IVD water content, all testing was performed aer midday. Upon
arriving at the radiology facility, participants were required to sit for a minimum of 20 minutes prior to entering
the scanner with participants sitting for a mean(SD) of 44(16) minutes which did not dier between groups
(p > 0.19). During this time participants completed questionnaires detailing their gender, type of physical activity,
body height, and average sitting duration Monday to Friday. e runners also reported distance run per week,
time run per week and number of years of participation.
To quantify IVD T2-time and morphology, a spin-echo multi-echo sequences on a 3T Phillips Ingenia scanner
(Amsterdam, Netherlands) was used with spinal coils to collect images at 8 echo times (15.75, 36.75, 57.75, 78.75,
99.75, 120.75, 141.75 and 162.75 ms) from 13 sagittal anatomical slices each (thickness 3 mm; interslice distance:
1.5 mm; repetition time: 2000 ms, eld of view: 281 × 281 mm, image resolution: 0.366 mm per pixel) encom-
passing the entire lower spine from le to right. For radiological categorisation of IVD degeneration (Prrmann
grade), a sagittal plane T2-weighted sequence (15 slices, slice thickness: 3 mm, interslice distance: 1.5 mm, repeti-
tion time: 2600 ms, echo time: 70 ms, eld of view: 357 mm × 357 mm, resolution: 0.532 mm per pixel) was taken.
To quantify muscle morphology, a paraxial T1-weighted scan (repetition time: 800 ms, echo time: 9 ms, slice
thickness: 4 mm, interslice distance: 2 mm, eld of view: 258.68 × 258.68 mm, image resolution: 0.270 mm per
pixel) with ve groups of three slices each positioned at each vertebral body L1 to L5 and oriented to the vertebral
end-plates was performed. Data were exported for further oine processing.
Aer scanning, subjects were given a hip-mounted ActiGraph model GT3X+ (Pensacola, FL). Participants
were instructed to wear the ActiGraph during all waking hours except during water-based activities (e.g. swim-
ming and bathing) for eight consecutive days. Acceleration data were collected at 100 Hz with a ±6 g range and
12 bit analog to digital conversion.
Oine image processing and analysis. To ensure blinding of the examiner to oine image measure-
ments, each subject was assigned a random numeric code (obtained from A radiologist deter-
mined the Prrmann grade of each lumbar IVD (Table1) on sagittal T2-weighted images. Seven individuals had
a supernumerary lumbar vertebral segment and the additional IVD (designated L6/S1) in these subjects was not
included in analyses.
ImageJ 1.38x ( was used to perform all quantitative MRI measures. In the sagittal
spin-echo multi-echo images every IVD from T11/T12 to L5/S1 was measured. Aer segmenting the IVD, a
custom written ImageJ plugin (“ROI Analyzer”; was used to rotate the
region of interest to the horizontal and measure area, height, width and signal intensity of the IVD in its entirety
as well as in ve subregions from the anterior to posterior aspect of the disc. T2-time was calculated via linear t
to the natural logarithm of the image intensity in each of the eight MR echos. Similar parameters were generated
for each of the ve disc subregions and interpolated across the width of the IVD to generate the 3D plots pre-
sented in Fig.3. Volume of each IVD in each subject was calculated by linear interpolation of the area data from
all slices. e image number where each spinous process was best visible was noted. e vertebral body was also
segmented and vertebral body height measured in a similar fashion in order to calculate the ratio of IVD height to
vertebral body height, as a normalised indicator of IVD hypertrophy. e data from each lumbar IVD were also
averaged. With the exception of IVD volume (Table1), data averaged from the three images around the spinous
process were used in analysis.
In each of the paraxial T1-weighted images, area of the lumbar multidus, erector spinae, psoas and quadratus
lumborum were measured bilaterally from L1 to L5 as in prior work27. e muscle area averaged from all lumbar
levels was used in analysis.
3D accelerometry analysis. Once participants returned the Actigraph, raw data were downloaded from
the device and analysed with a custom-written Matlab script (R2015b, Mathworks, Inc., Natick, MA, USA).
Resultant acceleration was calculated from the 3-dimensional data, and used in all further analyses. No smooth-
ing was applied on the recorded signal.
Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
Mean amplitude deviation ( =
1, where n = number of data points in an epoch, i = data point
index, x = resultant acceleration,
= mean of the epoch, and vertical bars signify taking the absolute value)28 was
calculated from the resultant acceleration in non-overlapping 5 s epochs in 24 h segments starting at 6 am local
time for all of the recorded days. e 5 s epoch mean MADs were divided into 98 logarithmically equidistant bins
(= histogram) from 0 g to 2.5 g. Non-wear time was dened as any hours with standard deviation less than 0.024 g,
and any days with less than 10 h of total wear-time were excluded from analysis. Data from individuals with 3
days of sucient wear-time were included. 70 individuals completed the Actigraph data collection and were
included in the analysis. Two individuals from the no-sport group, six from the jogging group and one from the
long-distance running group did not complete this data collection. On average, 7.6 days of complete data were
available per participant (similar across all three groups, p = 0.9). e mean of all included days is reported.
Additional sub-study: which activities generate what accelerations? To relate MAD to physical
activities, 10 individuals performed a graded treadmill test at speeds of 0.5 m/s, 1 m/s, 1.5 m/s, 2 m/s, 2.5 m/s,
3.0 m/s and 3.5 m/s whilst wearing a hip-mounted ActiGraph. At each speed, 70 seconds of data were collected
and the data from the 11 second onwards was used for further analysis. Participants also performed 10 consec-
utive jumps maintaining the knee and hip at near full extension (similar to hopping on one leg, but bilaterally).
Statistical analyses. An alpha-level of 0.05 was taken for statistical signicance. For continuous variables,
T-tests were performed comparing the long-distance and jogging groups to the non-sport referent group. Primary
analysis evaluated IVD T2-time (composition measure) and IVD height to vertebral body height ratio (hypertrophy
measure) averaged across all lumbar levels. Data from individual vertebral levels were also evaluated. Dierence in
response between males and females was evaluated via two-way analysis of variance for ‘group’ and ‘gender’. For com-
paring physical activity to IVD characteristics, the correlation and 95% condence interval was calculated between
number of counts for each subject in the MAD bin and the average lumbar IVD T2-time in the nucleus (central
subregion). e mean and 95% condence interval of the MADs in each of the physical activities of the sub-study
were calculated. e “R” statistical environment (version 2.10.1, was used for all analyses.
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Scientific RepoRts | 7:45975 | DOI: 10.1038/srep45975
We thank the subjects for participating in the study. We also thank the sta at Imaging at Olympic Park for their
support in implementing the study. is project was supported by internal institutional funding from Deakin
University School of Exercise and Nutrition Sciences (reference number ‘Belavy 2014–2017 ).
Author Contributions
D.L.B.: Contributed conception and design of the experiments, image analysis, statistical analysis, interpretation
of the data, draing the article. M.Q.: contributed subject recruitment, data collection, image analysis, approved
manuscript. N.R.: contributed to conception and design of the experiments, analysis of actigraph data, revision of
the manuscript, approved manuscript. Y.L.: contributed radiological assessment of images, approved manuscript.
D.C.: contributed to conception and design of the experiments, support with data collection, interpretation of
the data, approved manuscript. T.R . : contributed to conception and design of the experiments, data analysis,
statistical analysis, draing manuscript, approved manuscript.
Additional Information
Supplementary information accompanies this paper at
Competing Interests: e authors declare no competing nancial interests.
How to cite this article: Belavý, D. L. et al. Running exercise strengthens the intervertebral disc. Sci. Rep. 7,
45975; doi: 10.1038/srep45975 (2017).
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© e Author(s) 2017
... Moving habits that were generally less related with IVD degeneration were sitting (office 19 workers) (Luoma et al., 2000) and walking (Belavý et al., 2017;Takatalo et al., 2017) . In 20 contrast, moving habits classically related to IVD degeneration or to catabolic changes in NP 21 cell responses were weight lifting (Videman et al., 1995), heavy work (carpenters) (Luoma et 22 al., 2000) or whole body vibration exposure (machine drivers) (Luoma et al., 2000). ...
... or 65 jogging was found to be beneficial compared to a non-physiologically active control group 66(Belavý et al., 2017;Mitchell et al., 2020). Assuming that the chronicity of cell stressors is 67 crucial in the dynamics of IVD degeneration, as suggested by the model predictions, a frequent 68 switch among different moving habits can contribute to reduce the risk of IVD degeneration 69 and/or decelerate its development.70 ...
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Current methodologies to estimate cell responses usually focus on bottom-up intracellular network modeling, accompanied by limitations regarding the network topology and regarding the consideration of transient changes in cell responses due to chronic, dose-dependent stimulus exposure. Here we present a novel high-level top-down network modelling approach to simulate dose- and time-dependent cell responses within heterogeneous multifactorial, multicellular environments. Through the representation of cell activities as time-dependent parallel networks (PN t ), the PN t -Methodology provides relative, interrelated cell responses for heterogeneous stimulus environments. The methodology is based on a systematic use of experimental findings, both data- and knowledge-based. Applied to intervertebral disc multicellular systems, the PN t -Methodology allows for the first time to obtain qualitatively validated cell responses for daily human moving activities and exposure to microgravity. The PN t -Methodology is not tissue specific per-se and is designed to be easily scalable. Eventually, it provides a one-of-a-kind network modeling approach to approximate complex multicellular systems.
... Recent studies in humans reported that exercise can be beneficial for the intervertebral discs and provide support for the notion that specific exercise protocols may improve intervertebral discs material properties in the spine (113). In humans, some studies have shown the beneficial effects of aerobic and resistance exercises in adult and geriatric populations (34, [114][115][116][117][118][119]. ...
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There has long been discussion regarding the positive effects of physical exercise on brain activity. Exercising is used as a non-pharmacological treatment in many chronic diseases. Exercise has been shown to have beneficial effects on brain functions in humans and animals and, therefore, exercise is very important for brain rehabilitation and remodeling. Several studies have shown the beneficial effects of aerobic and resistance exercises in adult and geriatric populations. In addition, physical activity may improve self-esteem and feelings of self-worth in young adults.
... It is unknown if intervertebral disc hypertrophy is clinically revelant or protective; however, hypertrophy appears to be possible in the intervertebral disc. 18 It is currently unknown what mode of stress or dosage is optimal for intervertebral disc hypertrophy. If a clinician's goal is to optimize movement by building tissue up, then physical stress levels that overload the tissue are required. ...
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Lifting something off the ground is an essential task and lifting is a documented risk factor for low back pain (LBP). The standard lifting techniques are stoop (lifting with your back), squat (lifting with your legs), and semi-squat (midway between stoop and squat). Most clinicians believe the squat technique is optimal; however, training on squat lifting does not prevent LBP and utilizing greater lumbar flexion (i.e. stoop) when lifting is not a risk factor for LBP. The disconnect between what occurs in clinical practice and what the evidence suggests has resulted in ongoing debate. Clinicians must ask the right questions in order to apply the evidence appropriately. A proposed clinical framework of calm tissue down, build tissue up, improve work capacity can be used to determine which lifting technique is optimal for a patient at any given time. When applying this clinical framework, clinicians should consider metabolic, biomechanical, physical stress tolerance, and pain factors in order to address the movement system. For example, stoop lifting is more metabolically efficient and less challenging to the cardiopulmonary system. There may be few biomechanical differences in spinal postures and gross loads on the lumbar spine between stoop, squat, and semi-squat lifting; however, each lift has distinct kinematic patterns that affects muscle activation patterns, and ultimately the movement system. Clinicians must find the optimal dosage of physical stress to address all aspects of the movement system to minimize the risk of injury. There is no universal consensus on the optimal lifting technique which will satisfy every situation; however, there may be a lifting technique that optimizes movement to achieve a specific outcome. The calm tissue down, build tissue up, improve work capacity framework offers an approach to determine the best lifting technique for an individual patient at any give time. Level of evidence: 5.
... Physical activity (PA) is important for all body systems and general health as PA reduces the risk of obesity, osteoarthritis and the development of chronic pain [1][2][3][4][5][6][7] . Surrogate measures for PA include the number of steps per day (steps/day) and the amount of moderate to vigorous physical activity (MVPA). ...
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Background: The effect of lumbar decompression on physical activity (PA) measures (measured as number of steps/day and as moderate to vigorous PA (MVPA)) is poorly understood. The aim of the current study was to compare PA in patients before and after lumbar decompression and to determine the association between change in steps/day and MVPA with change in disability, health-related quality of life (HRQOL) and pain. Methods: Patients undergoing lumbar decompression surgery were recruited. Steps/day and MVPA MVPA were recorded with an accelerometer. Oswestry Disability Index (ODI), HRQOL (Short Form 36 questionnaire (SF-36)) and pain levels (visual analogue scale (VAS)) were collected prior to surgery and six and twelve weeks postoperatively. Steps/day were compared to the lower bound of steps/day in healthy persons (7,000 steps per day), and the relationship between changes in steps/day, MVPA, ODI, SF-36, and VAS were calculated. Results: Twenty-six patients aged 37 to 75 years met inclusion criteria and were included in the study. Lumbar decompressions were performed for stenosis and/or disc herniation. Preoperatively, patients took an average 5,073±2,621 (mean±standard deviation) steps/day. At 6 weeks postoperatively, patients took 6,131±2,343 steps/day. At 12 weeks postoperatively, patients took 5,683±2,128 steps/day. Postoperative MVPA minutes per week increased compared to preoperative MVPA (preoperative: 94.6±122.9; 6 weeks: 173.9±181.9; 12 weeks: 145.7±132.8). From preoperative to 12 weeks postoperative, change in steps correlated with MVPA (R=0.775; P<0.001), but not with ODI (R=0.069; P=0.739), SF-36 (R=0.138; P=0.371), VAS in the back (R=0.230; P=0.259) or VAS in the leg (R=-0.123; P=0.550). Conclusions: During the first 12 postoperative weeks, daily steps did not reach the lower bound of normal step activity of 7,000 steps/day, however postoperative steps/day were higher than before surgery. Steps/day and MVPA appear to be independent of ODI and SF-36 and represent additional outcome parameters in patients undergoing lumbar decompression surgery and should be considered e.g., by physiotherapists especially from 6 to 12 weeks postoperatively. Level of evidence: 2, prospective cohort study.
... Studies have shown that using MR-T1ρ sequence to quantitatively evaluate nucleus pulposus tissue proteoglycan is superior to other magnetic resonance sequences (14). Because MR-T1ρ imaging technology is sensitive to the low-frequency movement of macromolecular substances, and the proteoglycan molecules in the nucleus pulposus tissue of the intervertebral disc are macromolecular substances, MR-T1ρ technology can be used to quantitatively evaluate the proteoglycan content in the nucleus pulposus tissue of the intervertebral disc (15,16). Previous studies have shown that the T1ρ relaxation time is significantly and positively correlated with the proteoglycan content of human or animal lumbar intervertebral discs (17,18). ...
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Background: The aim of the present study was to construct an in vitro model of degenerated nucleus pulposus with different combinations of biochemical components, and to find an in vitro model for the early degeneration of nucleus pulposus suitable for the detection of magnetic resonance T1rho (MR-T1ρ) sequence for the early diagnosis of degeneration of lumbar intervertebral disc. Methods: The proteoglycan concentration gradient in the first experimental group was 5%, with a concentration range of 7 samples in vitro models from 5% to 35%. The second experimental group had 15 samples with a 1% concentration gradient of proteoglycan (range, 10-24%), with a higher water content compared with the first group. The third experimental group contained 20 samples with a concentration gradient of 1% proteoglycan (range, 10-29%), with 75% water content. All of the in vitro models were scanned using a 3.0T GE MR. To analyze the correlation between the proteoglycan content of the in vitro model and the T1ρ value, we investigated the feasibility and stability of modeling. Results: There was no correlation between the in vitro model proteoglycan concentration and T1ρ value in the first experimental group; however, there was a significant negative correlation between the proteoglycan concentration and T1ρ value in the second experimental group (Y=-3.02X+131.8, R2=0.852, P<0.05). In the third experimental group, the proteoglycan concentration was significantly positively correlated with T1ρ value (Y=3.05X+11.99, R2=0.834, P<0.05). The comparison of the T1ρ values in the third experimental group before and 3 months after yielded an intraclass correlation coefficient value of 0.980, indicating that the biochemical components in the third experimental group were still stable after 3 months of storage. The slope of the regression equation between the Pfirrmann grading and T1ρ value in the third experimental group was not statistically different from the volunteer group (F=0.54, P=0.814), suggesting that the lumbar disc nucleus pulposus tissue of in vitro model samples fitted well with the volunteer group. Conclusions: In this experiment, we successfully constructed an in vitro model of nucleus pulposus tissue proteoglycan that can be used for the quantitative evaluation of the MR-T1ρ imaging.
... A 6-month randomized control trial involving 40 patients found no significant difference between the control group and the exercising counterparts on the symptom of chronic low back pain [86]. While another research argued that human IVD responds positively to running exercise [87]. It may be difficult to define the effect of exercise on IDD and disc aging, but long sedentary work and disuse of motor system are not helpful for the control of IVD disorders. ...
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As part of the motor system, intervertebral disc (IVD) is a complicated tissue with multiple components. The degeneration of IVD may result in low back pain (LBP), which strongly impairs quality of life. Various causes are related to the degeneration of IVD, including cell senescence, hydration lost, and inflammation. Stem cells founded in different tissues have attracted the interest of the researchers and clinicians to study the implication of these cells in the treatment for tissue injury and degeneration. In this report, we will review the study of stem cells in the treatment for IVD degeneration. On the other hand, the effect of exercise on IVD degeneration and the relationship between IVD degeneration and musculoskeletal disorders like sarcopenia are discussed.
In diesem Kapitel sind wichtige Tests und Untersuchungsmethoden aufgeführt, mit denen die Kontraindikationen für eine osteopathische Behandlung erkannt werden können.
Intervertebral disc disease (IVDD) refers to degenerative processes of the spine resulting in reduced shock-absorbing ability, which may ultimately lead to disc herniation and spinal cord compression. Back pain is associated with this condition, representing the clinical feature mostly frequently referred by the patients. In this contribution, we analysed a recent review published in the Journal of Investigative Surgery, which discusses the mechanisms of the ROS production in IVDD with respect to resveratrol activity.
Objective: Habitual walking is important for health and can be measured with accelerometry, but accelerometry does not measure physiological effort relative to capacity. We compared accelerometer-measured absolute intensity and electromyography (EMG)-measured relative muscle activity between people with low versus excellent aerobic fitness levels during their habitual walking. Methods: Forty volunteers (19 women; age 49.3 ± 17.1 years, body mass index 24.0 ± 2.6 kg/m2; peak oxygen uptake 40.3 ± 12.5 ml/kg/min) wore EMG-shorts and a hip-worn accelerometer simultaneously for 11.6 ± 2.2 hr on 1.7 ± 1.1 days. Continuous gait bouts of at least 5-min duration were identified based on acceleration mean amplitude deviation (MAD, in milli gravitational acceleration, mg) and mean EMG amplitude, with EMG normalized to maximal isometric knee extension and flexion (EMG, in percentage of maximal voluntary contraction EMG). Peak oxygen uptake was measured on a treadmill and maximal strength in isometric leg press (leg press max). MAD and EMG were compared between age- and sex-specific fitness groups (low-average, good, and excellent) and in linear models. Results: During habitual walking bouts (4.1 ± 4.1 bouts/day, 0.9 ± 1.0 min/bout), the low-average fit participants had an approximately 28% lower MAD (245 ± 64.3 mg) compared with both good fit and excellent fit participants (313 ± 68.1 mg, p < .05), but EMG was the same (13.1% ± 8.42% maximal voluntary contraction EMG, p = .10). Absolute, relative to body mass, and relative to skeletal muscle mass peak oxygen uptake (but not leg press max) was positively associated with MAD independent of age and sex (p < .01), but there were no associations with EMG. Conclusions: People with low-average aerobic capacity habitually walk with a lower accelerometer-measured absolute intensity, but the physiological stimulus for lower-extremity muscles is similar to those with excellent aerobic capacity. This should be considered when measuring and prescribing walking for health.
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Background Osteoporosis and postmenopausal bone loss pose a huge social and economic burden worldwide. Regular exercise and physical activity are effective interventions for maximizing or maintaining peak bone mass and preventing bone loss in the elderly; however, most recommendations are addressed to the general public and lack specific indications for girls and women, the segment of the population most at risk for developing osteoporosis. Objective The aim of this overview of systematic reviews and meta-analyses was to summarize current evidence for the effects of exercise and physical activity interventions on bone status in girls and women, and to explore whether specific exercise programs exist for improving or maintaining bone mass or bone strength in females. Methods The PubMed, EMBASE, PEDro, and Cochrane Library databases were searched from January 2009, updated to 22 June 2015, using the following groups of search terms: (i) ‘physical activity’ and ‘exercise’; and (ii) ‘bone’, ‘bone health’, ‘bone strength’, ‘bone structure’, ‘bone metabolism’, ‘bone turnover’, and ‘bone biomarkers’. Searches and screening were limited to systematic reviews or meta-analyses of studies in females and published in English. Our final analysis included 12 articles that met the inclusion criteria. Results Combined-impact exercise protocols (impact exercise with resistance training) are the best choice to preserve/improve bone mineral density in pre- and postmenopausal women. Peak bone mass in young girls can be improved with short bouts of school-based high-impact plyometric exercise programs. Whole-body vibration exercises have no beneficial effects on bone in postmenopausal or elderly women. Conclusions and Implications Lifelong exercise, specific for age, is an effective way to sustain bone health in girls and women.
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To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a narrative review. The majority of the available data come from cell or whole-disc loading models and animal exercise models. However, some studies have examined the impact of specific sports on IVD degeneration in humans and acute exercise on disc size. Based on the data available in the literature, loading types that are likely beneficial to the IVD are dynamic, axial, at slow to moderate movement speeds, and of a magnitude experienced in walking and jogging. Static loading, torsional loading, flexion with compression, rapid loading, high-impact loading and explosive tasks are likely detrimental for the IVD. Reduced physical activity and disuse appear to be detrimental for the IVD. We also consider the impact of genetics and the likelihood of a 'critical period' for the effect of exercise in IVD development. The current review summarises the literature to increase awareness amongst exercise, rehabilitation and ergonomic professionals regarding IVD health and provides recommendations on future directions in research.
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Using data from 16 published reports, the authors correlated macroscopic disc degeneration grades with age, sex, and spine level In 600 lumbar Intervertebral discs from 273 cadavers (ages: 0-96 years). Male discs were more degenerated than female discs at most ages; significantly so In the second, fifth, sixth, and seventh decades. On average, L4-L5 and L3-L4 level discs showed more degeneration than discs at other lumbar levels. These macroscopic findings corroborate radio-graphic data from epldemlologlc studies. The calculations suggest that higher mechanical stress, perhaps combined with longer nutritional pathways, may be responsible for the earlier degeneration of male discs.
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Accelerometers are increasingly used for objective assessment of physical activity. However, because of lack of the proprietary analysis algorithms, direct comparisons between accelerometer brands are difficult. In this study, we propose and evaluate open source methods for commensurate assessment of raw accelerometer data irrespective of the brand. Twenty-one participants carried simultaneously three different tri-axial accelerometers on their waist during five different sedentary activities and five different intensity levels of bipedal movement from slow walking to running. Several time and frequency domain traits were calculated from the measured raw data, and their performance in classifying the activities was compared. Of the several traits, the mean amplitude deviation (MAD) provided consistently the best performance in separating the sedentary activities and different speeds of bipedal movement from each other. Most importantly, the universal cut-off limits based on MAD classified sedentary activities and different intensity levels of walking and running equally well for all three accelerometer brands and reached at least 97% sensitivity and specificity in each case. Irrespective of the accelerometer brand, a simply calculable MAD with universal cut-off limits provides a universal method to evaluate physical activity and sedentary behaviour using raw accelerometer data. A broader application of the present approach is expected to render different accelerometer studies directly comparable with each other.
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Background: Measuring disease and injury burden in populations requires a composite metric that captures both premature mortality and the prevalence and severity of ill-health. The 1990 Global Burden of Disease study proposed disability-adjusted life years (DALYs) to measure disease burden. No comprehensive update of disease burden worldwide incorporating a systematic reassessment of disease and injury-specific epidemiology has been done since the 1990 study. We aimed to calculate disease burden worldwide and for 21 regions for 1990, 2005, and 2010 with methods to enable meaningful comparisons over time. Methods: We calculated DALYs as the sum of years of life lost (YLLs) and years lived with disability (YLDs). DALYs were calculated for 291 causes, 20 age groups, both sexes, and for 187 countries, and aggregated to regional and global estimates of disease burden for three points in time with strictly comparable definitions and methods. YLLs were calculated from age-sex-country-time-specific estimates of mortality by cause, with death by standardised lost life expectancy at each age. YLDs were calculated as prevalence of 1160 disabling sequelae, by age, sex, and cause, and weighted by new disability weights for each health state. Neither YLLs nor YLDs were age-weighted or discounted. Uncertainty around cause-specific DALYs was calculated incorporating uncertainty in levels of all-cause mortality, cause-specific mortality, prevalence, and disability weights. Findings: Global DALYs remained stable from 1990 (2·503 billion) to 2010 (2·490 billion). Crude DALYs per 1000 decreased by 23% (472 per 1000 to 361 per 1000). An important shift has occurred in DALY composition with the contribution of deaths and disability among children (younger than 5 years of age) declining from 41% of global DALYs in 1990 to 25% in 2010. YLLs typically account for about half of disease burden in more developed regions (high-income Asia Pacific, western Europe, high-income North America, and Australasia), rising to over 80% of DALYs in sub-Saharan Africa. In 1990, 47% of DALYs worldwide were from communicable, maternal, neonatal, and nutritional disorders, 43% from non-communicable diseases, and 10% from injuries. By 2010, this had shifted to 35%, 54%, and 11%, respectively. Ischaemic heart disease was the leading cause of DALYs worldwide in 2010 (up from fourth rank in 1990, increasing by 29%), followed by lower respiratory infections (top rank in 1990; 44% decline in DALYs), stroke (fifth in 1990; 19% increase), diarrhoeal diseases (second in 1990; 51% decrease), and HIV/AIDS (33rd in 1990; 351% increase). Major depressive disorder increased from 15th to 11th rank (37% increase) and road injury from 12th to 10th rank (34% increase). Substantial heterogeneity exists in rankings of leading causes of disease burden among regions. Interpretation: Global disease burden has continued to shift away from communicable to non-communicable diseases and from premature death to years lived with disability. In sub-Saharan Africa, however, many communicable, maternal, neonatal, and nutritional disorders remain the dominant causes of disease burden. The rising burden from mental and behavioural disorders, musculoskeletal disorders, and diabetes will impose new challenges on health systems. Regional heterogeneity highlights the importance of understanding local burden of disease and setting goals and targets for the post-2015 agenda taking such patterns into account. Because of improved definitions, methods, and data, these results for 1990 and 2010 supersede all previously published Global Burden of Disease results. Funding: Bill & Melinda Gates Foundation.
1. Compression forces are mainly absorbed by the vertebral body. The nucleus pulposus, being liquid, is incompressible. The tense annulus bulges very little. On compression the vertebral end-plate bulges and blood is forced out of the cancellous bone of the vertebral body into the perivertebral sinuses. This appears to be the normal energy-dissipating mechanism on compression. 2. The normal disc is very resistant to compression. The nucleus pulposus does not alter in shape or position on compression or flexion. It plays no active part in producing a disc prolapse. On compression the vertebral body always breaks before the normal disc gives way. The vertebral end-plate bulges and then breaks, leading to a vertical fracture. If the nucleus pulposus has lost its turgor there is abnormal mobility between the vertebral bodies. On very gentle compression or flexion movement the annulus protrudes on the concave aspect–not on the convex side as has been supposed. 3. Disc prolapse consists primarily of annulus; it occurs only if the nucleus pulposus has lost its turgor. It then occurs very easily as the annulus now bulges like a flat tyre. 4. I have never succeeded in producing rupture of normal spinal ligaments by hyperextension or hyperflexion. Before rupture occurs the bone sustains a compression fracture. On the other hand horizontal shear, and particularly rotation forces, can easily cause ligamentous rupture and dislocation. 5. A combination of rotation and compression can produce almost every variety of spinal injury. In the cervical region subluxation with spontaneous reduction can be easily produced by rotation. If disc turgor is impaired this may occur with an intact anterior longitudinal ligament and explains those cases of tetraplegia without radiological changes or a torn anterior longitudinal ligament. The anterior longitudinal ligament can easily be ruptured by a rotation force and in my experience the so-called hyperextension and hyperflexion injuries are really rotation injuries. 6. Hyperflexion of the cervical spine or upper thoracic spine is an anatomical impossibility. In all spinal dislocations a body fracture may or may not occur with the dislocation, depending upon the degree of associated compression. In general, rotation forces produce dislocations, whereas compression forces produce fractures.
Sixty-one lumbar intervertebral joints were compressed while wedged to simulate hyperflexion. Twenty-six of the joints failed by posterior disc prolapse. The results show that slightly degenerated discs at lower lumbar levels from subjects aged between 40 and 50 years are most susceptible to prolapse.
SUMMARY In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 dIwkj1 for novice training, 3-4 dIwkj1 for intermediate training, and 4-5 dIwkj1 for advanced training. Similar program designs are recom- mended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance training, it is recommended that light to moderate loads (40-60% of 1 RM) be performed for high repetitions (915) using short rest periods (G90 s). In the interpretation of this position stand as with prior ones, recommendations should be applied in context and should be contingent upon an individual's target goals, physical capacity, and training